Ethanol has paradoxical effects on the human myocardium; consumption of large amounts over a lifetime can lead to alcoholic cardiomyopathy, whereas consumption of ethanol in moderation can prevent or reduce the risk of coronary artery disease (CAD) and cardiac ischemia. In addition to the preventive effect of moderate consumption of ethanol on CAD, acute exposure to ethanol induces a direct protective effect on the myocardium. This latter mode of protection by ethanol is thought to mimic a natural form of cardioprotection, termed ischemic preconditioning. However, the cardioprotective effect of ethanol appears to have a narrow therapeutic window; ethanol exerts both negative and positive effects on the myocardium. Identifying the mediators of ethanol's effects on the heart and identifying means to selectively activate those that are cardioprotective and inhibit those that contribute to cardiac damage may enable the use of ethanol in prevention of cardiac damage during or after acute MI. The research proposal described above focuses on one scenario - the effect of acute exposure to ethanol on the response of the heart to ischemia and reperfusion. We plan to determine the role of ethanol on the activities of mitochondrial enzymes that correlate with the cardioprotective effect of ethanol (AIM 1), identify ethanol-induced PKC-selective substrates and their role in cardioprotection (AIM 2) and determine whether acute treatment with ethanol can be used as a cardioprotective agent in a large animal model of transient ischemia and reperfusion in vivo (AIM 3). Together, our studies will assess the molecular basis and potential use of ethanol as an agent to protect the heart from ischemic damage.